SURF matching

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0 个投票

SURF descriptor will extract one vector with length 64. If i want to match between two regions, how am i going to match this two descriptor?i search a lot of information and mostly they use euclidean distance to get the value. if i use euclidean distance, how can i going to do that? by minus each 64 value with other 64 values in the other region? or each one value compare with other 64 value?if 64 * 64 =4096, then the process will be very time consuming! anyone pls answer me?!

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Jan 2011-8-15

Please post more details, most of all the code you have created already.

km g 2011-8-16

length=20*s/2;

g=fspecial('gaussian',[(2*length)+1 (2*length)+1],3.3*s);

theta=-direction*pi/180;

[diy,dix]=ndgrid(-length-1:length+1,-length-1:length+1);

test(1:200,1:200)=0;

for m=1:size(dix,1)

for n=1:size(dix,2)

test(r+diy(m,n),c+dix(m,n))=z1(r+diy(m,n),c+dix(m,n));

end

for m=1:size(diy,1)

for n=1:size(diy,2)

newx(m,n)=(dix(m,n)*cos(theta))-(diy(m,n)*sin(theta));

newy(m,n)=(dix(m,n)*sin(theta))+(diy(m,n)*cos(theta));

end

cox=round(c+newx);

coy=round(r+newy);

cox=cox(:);

coy=coy(:);

test2(1:200,1:200)=0;

for cc=1:size(cox,1)

newmapping(cc)= z1(coy(cc),cox(cc));

test2(coy(cc),cox(cc))=z1(coy(cc),cox(cc));

end

newmapping=reshape(newmapping,23,23);

figure,imshow(test,[]);

figure,imshow(test2,[]);

figure,imshow(newmapping,[]);

% g=g(:);

sizec=2*s;

sizer=2*s;

%

% nhaarx(1:200,1:200)=NaN;

% nhaary(1:200,1:200)=NaN;

for cc=2:22

for rr=2:22

nhaarx(rr-1,cc-1)=(boxintegral(rr-sizer/2,cc,newmapping,sizec/2,sizer)-boxintegral(rr-sizer/2,cc-sizec/2,newmapping,sizec/2,sizer));

nhaary(rr-1,cc-1)=(boxintegral(rr,cc-sizec/2,newmapping,sizec,sizer/2)-boxintegral(rr-sizer/2,cc-sizec/2,newmapping,sizec,sizer/2));

end

%

% figure,imshow(nhaarx,[]);

% figure,imshow(nhaary,[]);

for m=1:size(nhaarx,1)

for n=1:size(nhaary,2)

if dix(m,n)==0 || diy(m,n)==0

nhaarx(m,n)=NaN;

nhaary(m,n)=NaN;

end

q=1;

for m=1:size(nhaarx,1)

for n=1:size(nhaarx,2)

if isnan(nhaarx(m,n))==0 && isnan(nhaary(m,n))==0

newregionxx(q,1)=nhaarx(m,n);

newregionyy(q,1)=nhaary(m,n);

q=q+1;

end

si=sqrt(size(newregionxx,1)*size(newregionxx,2));

newregionx=reshape(newregionxx(:,1),si,si);

newregiony=reshape(newregionyy(:,1),si,si);

figure,imshow(newregionx,[]);

figure,imshow(newregiony,[]);

p=1;

gap=20*s/4;

for m=1:gap:size(newregionx,1)

for n=1:gap:size(newregiony,1)

[sumx,sumax,sumy,sumay]=getvector(m,n,gap,newregionx,newregiony);

sx(p)=sumx;

sy(p)=sumy;

sax(p)=sumax;

say(p)=sumay;

p=p+1;

end

descriptorv(1:16)=sx(:);

descriptorv(17:32)=sy(:);

descriptorv(33:48)=sax(:);

descriptorv(49:64)=say(:);

descriptorvv(1:16)=sy(:);

descriptorvv(17:32)=sx(:);

descriptorvv(33:48)=say(:);

descriptorvv(49:64)=sax(:);

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Answer 1

David Young 2011-8-15

在 MATLAB Online 中打开

0 个投票

The Euclidean distance between vectors A and B is computed simply using

norm(A-B)

This applies to SURF descriptor vectors too.

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David Young 2011-8-17

You can either rotate the image patch, or you can rotate the kernels, but not both.

km g 2011-8-18

if i rotate the image patch, then do i need to compute the integral image again for the rotated image patch?or i directly use the integral image of that part by using the one that compute earlier?

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